Submission #759662

#	Time	Username	Problem	Language	Result	Execution time	Memory
759662		IvanJ	Sequence (APIO23_sequence)	C++17	28 / 100	2068 ms	18648 KiB

sequence

#include "sequence.h"
#include<bits/stdc++.h>

#define pb push_back
#define x first
#define y second
#define all(a) (a).begin(), (a).end()

using namespace std;

typedef long long ll;
typedef pair<int, int> ii;

struct tree {
	int pot;
	vector<int> T;
	void init(int N) {
		pot = 1;
		while(pot < N) pot <<= 1;
		for(int i = 0;i < pot * 2;i++) T.pb(0);
	}
	
	void add(int x) {
		x += pot;
		T[x]++;
		x >>= 1;
		while(x > 0) T[x] = T[x * 2] + T[x * 2 + 1], x >>= 1;
	}
	
	int find(int x, int lo, int hi, int target) {
		if(lo == hi) return lo;
		int mid = (lo + hi) / 2;
		if(T[x * 2] >= target) 
			return find(x * 2, lo, mid, target);
		else 
			return find(x * 2 + 1, mid + 1, hi, target - T[x * 2]);
	}
	
	ii medians() {
		int K = T[1];
		int p1 = (K - 1) / 2 + 1;
		int p2 = K / 2 + 1;
		return {find(1, 0, pot - 1, p1), find(1, 0, pot - 1, p2)};
	}
};

int sequence(int N, vector<int> A) {
	tree T;
	T.init(N);
	for(int i = 0;i < N;i++) A[i]--;
	int ans = 0;
	for(int i = 0;i < N;i++) {
		vector<int> cnt(N, 0);
		tree T;
		T.init(N);
		for(int j = i;j < N;j++) {
			cnt[A[j]]++;
			T.add(A[j]);
			ii p = T.medians();
			ans = max(ans, max(cnt[p.x], cnt[p.y]));
		}
	}
	return ans;
}

• Subtask 1: 11 / 11
• Subtask 2: 17 / 17
• Subtask 3: 0 / 7
• Subtask 4: 0 / 12
• Subtask 5: 0 / 13
• Subtask 6: 0 / 22
• Subtask 7: 0 / 18